With the increase of wireless communication capacity, more and more advanced digital modulation schemes, e.g. Wideband Code Division Multiple Access (WCDMA), Long Term Evolution (LTE) and 5th-Generation (5G), Institute of Electrical and Electronics Engineers (IEEE) 802.11ac etc. are and will be involved which results in a high crest factor (CF) or a high peak to average power ratio (PAPR) of signal.
Radio frequency (RF) power amplifier (PA) is used in wireless communication networks for the transmission of signals. A peak to average power ratio can be computed from the CF. But high PAPR signal imposes significant operating restrictions on the RF power amplifier, causing lower average output power and efficiency.
To increase efficiency, crest factor reduction (CFR) can be used to decrease the PAPR of a transmitted signal prior to it entering the power amplifier. By doing so, the power amplifier can operate with less back off, and thus increased average efficiency.
Nowadays, numerous CFR methods have been developed. Peak-cancellation CFR (PC-CFR) is one of the CFR methods which have been widely used. The system level performance of the PC-CFR method is shown to be better than other methods such as Peak Windowing and Noise Shaping. In addition, the PC-CFR can be implemented more efficiently than the other methods, resulting in reduced overall cost.
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